This invention relates to a vibro pile hammer, and more particularly to a multi-vibro pile hammer for generating vibrations with different or reversed phases.
The vibro pile hammer of the kind specified which has heretofore been used comprises a driving means, a vibration generating unit, a power transmission means for connecting and driving the two, and a clamping means adapted to clamp piles or sheet piles, and is suspended through spring means from a stand so that vibrations caused by the vibration generating units can be transmitted to the piles or sheet piles to be driven underground or pulled out therefrom thereby reducing the noise level.
However, since the above-mentioned conventional vibro pile hammers has employed a single set of hammer to carry out such work, a single vibration is transmitted to the ground thereby increasing the vibration transmitting region. Further, disclosed in Japanese Utility Model Laying Open Publication No. 147,403/1975 is an arrangement which comprises two sets of multi-vibro pile hammers installed in parallel relationship, which however can not reduce the underground vibration transmitting region because the two sets of vibro hammers generate vibrations with the same phase which are in synchronism.
Of late, vibrations of such a kind have been subjected to extremely severe controls by authorities concerned with increasing civil works in cities and the vibrations have been treated as a public hazard.